Improvement in artificial slate-pencils



106. cowosmons,

COAllNG 0R PLASllC CYOSS Relerence nmNHonD LANSTROM, or c1Nc1NNArI, 01110, ASSIGNOR T0 JOHN 0.

- ISHAM AND REUBEN F. access, or am PLAGE.

IMPROVEMENT IN ARTIFICIAL SLATE-PENOILS.

Specification forming part of Letters Patent No. 208,649, dated May 14, 1818; application filed April 8, 1878.

To all whom it my eoneem:

Be it known that I, RmNnoLn LANSTROM, of Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Slate-Pencils; and I do hereby declare that the following is a full, clear and exact description thereof, which will ehhhie others skilled in the art to which it hppertains to make and use the same, reference being had to this specification.

This invention relates to a new and improved composition slate-pencil and mode of making the same, as follows:

The composition of which the pencils are to he made is formed by making a preparation of six (6) parts blue calcareous cla org 5ft limestone four parts s a o 2) par a sfine two )partscarEnateofhme and t parts aolin, powdera, mix ed, and

dampened with silicate of soda and otash dried and l gated till it Wines llar l, and tlien'i'educed to a fine powder. To an: (6)

' parts of the a%ve preparation are now added two (2) partsfo us ca careous cla or :(ame proportion o sla'fi; Tour (I) part5 so a -s ne, two (2) parts car onate o lime and Ee (3) parts kaolin are finely pfilverlz' ed, moistening it, with amixture of sev'en-eighths G) part of silicagp of soda and one-eighth (5) part sili cate o to the consistency of a still morar.

The mass, after being thoroughly mixed, is then placedin-a cylinder under heavy ress ure, forming it into a solid body of suitable sii'eaiid shape to again be placed into a reeep 1e where it, under. pressure, is reduced either by molding or drawing to the shape of the pencils required, which may be of any approved size. The pencils are now placed on corrugated metallic plates, so constructed as to allow a free passage of air over the pencils when the plates are placed upon each other, and also to keep the pencils from bending during the drying process. The pencils are then placed in a dr ipg-house, and exposedto a hot-air blast andthen tempered in a heater com that purpose till may become sufficiently hard and complete.

In place of the first-named preparation, or incorporated in the same, I sometimes use scraps and broken ncils accumulated in the manu acture, ea mg an reducing the same to a fine powder, and again mixed with the above-named ingredients of clay or slate, soapstone carl onate of lime, kfi n, aridfsilicate fsoda apdpotash, in the proportions above mentioned, and producing the same result.

This composition makes a remarkably fine grade of pencil for slates, combining the softness of soap-stone and ease in writing with the soap-stone with the required oughness or hardness of the slate, making their use desirable and preferable in schools, 850. I

Having thus described my improved pencil and the manner of making the same, what claim as new and useful, and desireto secure by Letters Patent, is-- As a newarticle of manufacture, a--slatepencil composed of the following ingredients: blue calcareous clay or itsequivalent, slate, soap-stone, carbonate of lime, kaolin, silicates 'dfsodit and potash, in or about the proportions specified.

In testimony that I claim the foregoing as 'my own I hereby aflix my signature in presence of two-witnesses. I BEINHOLD LANTSTROM.

Witnesses: i

R.- F. Huenns, F. J. PAUL.

Ekanli nerjl 

